#!/usr/bin/ruby
 
class Customer
    @@no_of_customers=0
    def initialize(id, name, addr)
       @cust_id=id
       @cust_name=name
       @cust_addr=addr
    end
    def display_details()
       puts "Customer id #@cust_id"
       puts "Customer name #@cust_name"
       puts "Customer address #@cust_addr"
     end
     def total_no_of_customers()
        @@no_of_customers += 1
        puts "Total number of customers: #@@no_of_customers"
     end
 end
  
 # 创建对象
 cust1=Customer.new("1", "John", "Wisdom Apartments, Ludhiya")
 cust2=Customer.new("2", "Poul", "New Empire road, Khandala")
  
 # 调用方法
 cust1.total_no_of_customers()
 cust2.total_no_of_customers()